Conventional stringed musical instruments which have a hollow or semi-hollow body generate musical tones by strumming or plucking strings stretched over a bridge and saddle mounted on the sound board corresponding to the anatomical front of the musical instrument. Sound is produced by the vibration of the strings and transmitted from a bridge assembly, mounted upon the sound board, throughout the body of the musical instrument and exits through a sound hole in the musical instrument, generally located in the anatomical front sound board and usually underneath the strings.
In an acoustical guitar the hollow interior of the body forms an acoustical resonant enclosure which enhances and amplifies the sound generated from the sound board. The sound board of the musical instrument is conventionally understood to represent the top or front of the instrument. The rear or back of the guitar is not considered to have much, if any, significance relative to the overall sound generated by the musical instrument and, as such, little attention is given to the wood used in the construction of the rear board of the guitar. The front and rear boards are connected to the body of the instrument along the sides thereof to fully enclose the body surrounding the hollow interior. As explained above, the front board is recognized as the sound board of an acoustical guitar and is composed of expensive tone woods such as, for example, spruce and/or red cedar whereas the rear board is typically composed of inexpensive wood or other material. The front and rear boards of a conventional acoustical guitar usually includes ribs on the inner side of each board facing the interior of the guitar to add to the structural strength of each board respectively. However, in most cases, no structural support exists between the front and rear boards of a conventional acoustical guitar other than the support provided by the sides connecting the front to the rear board.
It has been discovered in accordance with the present invention that the sound produced from a stringed musical instrument can be enhanced by simultaneously utilizing both sound boards inclusive of both the front sound board and the rear sound board of the guitar for generating sound independent of one another utilizing a single set of guitar strings to interconnect the front sound board to the rear sound board through the interior of the guitar. This is accomplished in accordance with the present invention using a dual bridge and saddle assembly which includes a first bridge and saddle mounted on the front sound board of the musical instrument and a second bridge and saddle mounted on the rear sound board with a single set of guitar strings interconnecting the first bridge and the second bridge through the hollow interior of the guitar. The dual bridge and saddle assembly should preferably also include support posts connected between the first bridge and the second bridge through the interior of the guitar for providing additional structural support for the guitar between the front sound board and the rear sound board respectively and provide support due to any compromise of support from the presence of the dual bridge
By vibrating the common set of strings extending between the two sound boards, sound is transmitted from both the front and rear sound boards of the musical instrument throughout the musical instrument interior to generate a composite of acoustical sound having an intensity and frequency range greater than the intensity and frequency range otherwise generated from an acoustical guitar with the guitar strings connected only to the front sound board. Moreover, sound is further enhanced by coupling each sound board to its own separate sound (pre)amplifier and/or amplifier, which enables the sound produced from each sound board to be independently and separately controlled.
It is also preferred in accordance with the present invention, but not essential, that at least one of the sound boards, preferably the front sound board, include at least one sound port, in addition to the conventional sound hole, through which sound can exit from the guitar independent of the sound hole. The sound port may be located in the general vicinity of the sound hole and should comprise a hollow member of any desired geometry, preferably a tube adapted to be inserted through an opening formed in one of the sound boards, preferably the front sound board, with the hollow member having a length extending from the front sound board to a location within the hollow body of the instrument equal to 5% to 95% of the distance between the front sound board and the rear sound board and forming an opening through the front sound board of any desired size dimension preferably a round in geometry. By varying the extended length of the sound port within the interior of the guitar i.e., selecting a desired length from various different lengths each within the desired range depending on the sound intended the sound port can be tuned to different desired frequency ranges proportional to the resonant frequency of the guitar, e.g. to possess a higher and/or lower frequency spectrum corresponding to a treble or bass sound range different from the frequency spectrum of the sound exiting the sound hole thereby creating a greater dynamic frequency range produced by the musical instrument.
In addition, particularly when a sound port is added to the musical instrument, it is also preferable to include one or a plurality of panels in the body of the musical instrument connected between the front sound board and the rear sound board to funnel sound toward the sound port(s). The panel(s) should be arranged to lie between each sound port and the sound hole, generally but not limited to the upper bout of the guitar and extend preferably up to the neck of the guitar or may interconnect with another panel near the neck of the guitar. In this arrangement, the panels cause sound to be directionally funneled to each sound port and thereby exit the sound port(s) in addition to sound exiting the sound hole. Since the panel(s) are connected between the front and rear sound boards, the panel(s) will inherently provide structural support between the front and rear boards of the guitar serving as an alternative to the current standards and use of ribs on the front and/or rear sound boards in addition to support provided by use of the support posts in the dual bridge and saddle assembly.